1. Field of the Invention
The present invention relates to a printing apparatus, a storage medium having a program recorded thereon, a correction pattern, a computer system, and a printing method.
2. Description of the Related Art
Printing apparatuses such as inkjet printers comprise: a print head that ejects ink and that is provided on a carriage which performs scanning in the main-scanning direction, and a carrying device that carries a print sheet by a constant carry amount. Such printing apparatuses print by sequentially carrying the print sheet in correspondence with the printing operation of the print head. Thus, in order to achieve good printing, it is necessary to accurately carry the print sheet, and one method for this is disclosed in Japanese Patent Application Laid-open Publication No. 11-49399 (U.S. Pat. No. 6,101,426), which discloses a printing apparatus provided with a carrying device. A carry error, which appears at a specified period as the carry roller for carrying the print sheet rotates, is measured for the carrying device, this period is divided into a plurality of sections, and correction values of the carry errors for each section are set to the carry device during the manufacturing stage; the carry device carries the print sheet after the carry amount is corrected using the correction values.
However, for example, differences in the environment in which the printing apparatus is used, differences in the amount of change in the shape of the carry roller due to the thickness of the print sheet, and differences in the coefficient of friction among different types of print sheets, may change the carrying of the print sheets. This results in the problem that even if correction values for carry errors are set during manufacturing, the correction values that are set in the manufacturing stage may not always be the most appropriate depending on the usage environment of the user or the print sheets that are used, leading to instances where the print sheet is not carried appropriately.
Thus, a configuration that allows the user to correct the carry amount is preferable; however, if, as in the above, it is desired that the print sheet is carried with enough accuracy that the slightest change in the condition of the carry roller has to be corrected, then, to perform a more accurate correction, it is necessary to increase the number of sections into which the period is divided and to allow a large number of correction values to be set to each section. However, if the number of sections or the number of correction values is increased, although it may be possible for the user to correct the carry amount, it is difficult for users to determine an appropriate value for the correction amount, and no proposal has been made for determining means that allow this to be determined easily.